Introduction to GraphQL

Introduction to GraphQL by Anil Gurindapalli at XAMPR's workshop.

Transcript

1. GraphQL -Anil Gurindapalli @AGurindapalli
2. WHAT IS GraphQL? XAMPR 2
3. XAMPR • Declarative and data fetching Query Language. • Became Open Source in 2015 • Used in Production of Facebook Mobile Apps for data fetching. • Get Data from Server to client • Is used by companies like Netflix, Coursera, Pinterest, GitHub, etc. 3
4. WHY USE GraphQL? XAMPR 4
5. XAMPR • Over fetching and Under fetching • Multiple round trips • Performance Suffers THE PROBLEM 5
6. XAMPR 6
7. XAMPR Instead of having multiple “dumb” endpoints, have a single “smart” endpoint that can take in complex queries, and then massage the data output into whatever shape the client requires. SOLUTION 7
8. XAMPR 8
9. THREE MAIN CHARACTERISTICS 1. It lets the client specify exactly what data it needs. 2. It makes it easier to aggregate data from multiple sources. 3. It uses a type system to describe data. XAMPR 9
10. BENEFITS • Avoid Multiple REST Calls (Performance) • Client Determines shape and size (Flexibility) • Is Backward compatible and version-free (Evolution) • Can wrap around Existing API • Is language agnostic. • Immediate Productive (Developer Productivity) XAMPR 10
11. UNDERSTANDING GraphQL XAMPR 11
12. XAMPR 12
13. XAMPR 1. Queries 2. Schema 3. Resolver BUILDING BLOCKS OF GraphQL 13
14. XAMPR 14
15. ANATOMY OF GraphQL QUERY XAMPR 15
16. XAMPR 16
17. XAMPR 1. Query To GET the data 2. Mutation To POST the data OPERATION TYPES OF QUERY 17 query mutation
18. XAMPR 18 query
19. XAMPR 19 mutation
20. XAMPR 20
21. XAMPR 21 Schema
22. XAMPR 22
23. XAMPR 23
24. PHASES OF QUERY XAMPR 24
25. XAMPR Every Query goes through three phases 1. Parse 2. Validated 3. Executed 25 Parse Validate Execute
26. XAMPR  A query is parsed into an Abstract Syntax Tree (or AST). PARSE 26
27. VALIDATE   The AST is validated against the schema. Checks for correct query syntax and if the fields exist. XAMPR 27
28. EXECUTE  The runtime walks through the AST, starting from the root of the tree, invokes resolvers, collects up results, and emits JSON. XAMPR 28
29. HANDS ON XAMPR 29
30. REFERENCES • https://graphql.org/ • https://blog.apollographql.com/the-anatomy-of-a-graphql-query-6dffa9e9e747 • https://medium.freecodecamp.org/so-whats-this-graphql-thing-i-keep-hearing- about-baf4d36c20cf • https://medium.com/netflix-techblog/our-learnings-from-adopting-graphql- f099de39ae5f • https://medium.com/paypal-engineering/graphql-resolvers-best-practices- cd36fdbcef55 • https://code.fb.com/core-data/graphql-a-data-query-language/ XAMPR 30
31. THANK YOU XAMPR 31 @AGurindapalli